In a sewing machine, a pair of rod-like feed bars are incorporated in a cylinder, in order to convey a material for sequentially performing sewing. One feed bar and the other feed bar constituting the pair of feed bars are arranged parallel to each other on the left and right sides with respect to the longitudinal direction of the cylinder. Material feeders having feed dogs with projections and recesses are attached respectively to the distal ends of the feed bars. The respective feed bars move to draw elliptical trajectories in side view so that the feed dogs project and retract from the upper surface of a stitch plate. By the movement of the respective feed bars, the material located on the stitch plate is pressed by material feeders to be conveyed in one direction.
Oil is supplied to the feed bars for lubrication of the portions where the feed bars abut each other and lubrication between the inner wall of the cylinder and each feed bar. If the supplied lubricating oil reaches the material feeders at the distal ends of the feed bars along the surfaces of the feed bars, the lubricating oil adheres to the material, which is a problem. In order to prevent this problem, there are sewing machines including oil seals provided in feed bars. Such a sewing machine is disclosed, for example, in Patent Literature 1 as a “feed-off-arm-type sewing machine”.
In the sewing machine disclosed in Patent Literature 1, a rectangular plate-shaped oil seal (which is described as an “oil cutting tool” in Patent Literature 1) is attached so as to surround the periphery of a pair of feed bars. The oil seal is supported by a support frame fixed to a cylinder by screwing. The support frame is also substantially rectangular with four corners closed and is arranged so as to surround the periphery of the feed bars.
With the structure of the sewing machine disclosed in Patent Literature 1, a gap may possibly occur between the support frame and the inner wall of the cylinder when attaching the support frame to the inner wall of the cylinder, and if the lubricating oil passes through the gap, the lubricating oil reaches the distal ends of the feed bars. Therefore, in order to prevent oil leakage more reliably, a sealant is applied between the support frame and the inner wall of the cylinder. As such a sealant, a material that is in liquid form when applied and is solidified after the application is used, for example.
The cylinder has an opening that is open upward and is generally covered by a cover part. For the maintenance of the feed bars, the cover part is detached from the opening, and the pair of feed bars are raised upward so as to project through the opening. The oil seal and the support frame are arranged so as to surround the periphery of the pair of feed bars and therefore are raised together with the pair of feed bars.
The support frame disclosed in Patent Literature 1 is present so as to surround the periphery of the feed bars, and therefore it is necessary for maintenance of the feed bars to remove the screw fixing the support frame to the cylinder and to remove the sealant applied between the support frame and the inner wall of the cylinder once. Therefore, regardless of whether or not the oil seal is to be replaced in the maintenance, it has been necessary to remove the sealant at each time of maintenance of the feed bars and apply the sealant again after the completion of maintenance. In this way, the maintenance work of feed bars has been conventionally inconvenient.